Some herbivores such as horses have a gut with a spacious side pocket or a diverticulum at the junction of the small and large intestine called a cecum, which serives as a fermentation chamber and absorptive area. Fermentation takes place after the primary absorptive area.

Ruminants such as cattle, have a huge 4 chambered stomach. As a ruminant feeds, grass passes down the esophagous to the rumen, where it is broken down by microorganisms and then formed into small balls of cud.